Carbon canisters are continually being refined to decrease cost and improve fuel vapor recovery. One area of improvement has been to incorporate various elements of the carbon canister into a single molded structure to decrease costs. For example, the vapor inlet, the vapor outlet, as well as the canister housing have been incorporated into a single integrally molded structure to reduce manufacturing cost.
However, when the geometric complexity of the carbon canister is increased, various problems may arise during molding. For example, the complexity of the mold may create pressure imbalances within the mold due to the flow patterns that are generated. The pressure imbalances may cause stress failure of the tooling structure. Moreover, structural weakness and other manufacturing defects in the carbon canister may develop when there is a substantial pressure differential between regions of the carbon canister during molding. In particular lower wall thickness, voids, short shots, and other molding defects may occur when there is a pressure imbalance during manufacturing.
As such, various example systems and approaches are described herein. In one example, an integrally molded carbon canister is provided. The integrally molded carbon canister includes a housing including four external side walls and an upper portion at least partially enclosing an internal cavity with a vapor inlet and outlet port, the upper portion including a depressed flow disruptor positioned rearward of an injection gate, and a first and second projected flow channel positioned adjacent to the injection gate point and laterally spanning the housing.
In some examples the carbon canister may further include ribs traversing at least a portion of three of the side walls forward of the injection gate. The ribs may extend between the upper portion and the at least three side walls and converge with the projected flow channels at a partition wall spanning the internal cavity dividing the internal cavity into a first and second chamber. The depressed flow disruptor may be interposed by an injection gate for the polymer melt during molding included in an upper portion of the housing and a partition wall separating the internal cavity into a first and second internal chamber.
In this way, the flow rate of the polymer melt may be adjusted to decrease the pressure differential between various portion of the carbon canister during molding, thereby reducing the degradation (e.g., wall thinning, warping, etc.,) caused by pressure imbalances. Moreover, the amount of manufacturing defects may be reduced and the structural integrity of the carbon canister may be increased when these type of flow-balancing features are utilized.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.